Transformer structure



De@ 6, 1932; 1,s9o,o 45

S. WIDMER ETAL TRANSFORMER STRUCTURE Filed oct. 2. v 1951 I Patented- Dec. 6, 1932 'UNITED' "STATES PATENT ori-ica lSTEFAN WIDIIIIER.` AND MAX HBLIMANN, OF BADEN, SWITZERLAND, ASSIGNOBS TO AKTIENGESELLSCHAFT BROWN BOVECRI ET CIE., OF BADEN, SWITZERLAND, A JOINT- STOCK COMPANY OF SWITZERLAND mnANsroaMEa STRUCTURE Application llled October 2, 1931, Serial No. 566,484, and in Germany September 17, 1931.

This invention relates to improvements in transformer structures and particularly to transformers to be used for the purpose of supplying alternating current to. the parallel operating-anodes of an `electric power rectifier of the metal inclosed metallic vapor type.

therefore be produced in the several anode circuits in order that .the several parallel connected anodes of the same phase may be forced to carry a uniform current. Such additional drop can be obtained by means of f anode reactance coils or by dividing the secondary winding of each pha-se ofthe rectifier supply transformer in as many separated windings as there are arallel operating anodes. Suchdivisionoft esupplytransformer winding is not, however, in general, suicient to produce the necessary drop especially in the use of low direct volta es in rectiliers where the absolute amount o the stray volta e is small. A combination of both of the a ove named arrangements, namely, the se aration of the transformer secondary win ings of the A'parallel operating anodes of a rectifier into apluralit of sections with the addition of reactances has already been proosed. Such arran ement, however, has the isadvanta'ge that't e additional reactances make it very expensive.

Itis, therefore, anl object of the present invention to provide a -device for increasing the stray voltagedrop in the secondary windings of a transformer supplying parallel voperating anodes of an electric power rectifier.

Another ob'ect of the invention is to provide a device or increasing the'strafy voltage a transdropin the Isecondary windings o former supplying parallel operating anodes of an electric power rectifier in which trans- Six phase electric power rectiiers of the former the secondary winding portions are uniformly distributed relative to the primary Winding and are interleaved with each other.

Another object of the invention is to provide a devicefor increasing the stray voltage drop in the secondary windings of a transformer supplying parallel operating anodes of an electric power rectifier in which transformer the secondary winding portions are interleaved relative to each other and in which means are arranged in the stray path of the several winding portions to increase the stray voltage of such portions.

Another object of the invention is to proi vide a device for increasing the stray voltage drop 1n the secondary wlndings 0fa transformer supplying parallel operating anodes.

of an .electric power rectifier in which transformer the secondary winding portions are uniformly distributed over the primary winding and are interleaved with each other `and in which means in the form of cut out transformer.

Referring more particularly to the drawing by characters of reference, reference numeral 4 designates a fragment of a transformer core on which is wound a primar winding 5 which is surrounded by a secon ary winding divided into sections 6, 7 8 and 9. The secondary winding sections are similar and are uniformly distributed over the entire length of the primary winding. The several secondary wmding sections are connected into series connected groups for the purpose' of supplying parallel operating anodes of an electric power rectifier and the several sections of the several groups are interleaved. Thus secondary winding sections avoid short circuits thereof. The rings ma 6 and 8 are connected to form one group and sections 7 and 9.y form another group. It is desirable that the connections of the several groups be such that current iows through the groups in opposite directions to minimize the mechanical stresses on the structure. It will be understood that the windings of only one phase of a transformer structure have been shown and that the secondary windings have been shown as divided into only two groups to su ply two parallel operating anodes of a recti er. The secondary winding may, however, be divided into anynumber of groups dependentconly on the number of anodes to be supplied in arallel and provided only that the sections of) the winding groups vbe interleaved and uniformly distributed over the primary winding.

An insert of good magnetic conductive material such as iron is arranged between each two of the sections of the secondary winding and in spaced relation therefrom and from the primary winding. Such inserts are in the form, preferably, of interrupted rings to be solid as shown at 10 or may be made lami nated with the several laminations spaced from each other as shownat 11. Under some circumstances' it may be desirable to imbed each of the laminations within insulation as shown at 12 and to unite the several insulated laminations by pressure.

vThe stray voltage drop in windings is very much increased even at very low currents b the use of inserts such as above describe As soon, however, as the inserts are saturated the stray volta e dro will no longer increase proportionate y witii a further increase in current which is an advantage for .the reason that the stray voltage drop will not become too great at full load or at overload on the transformer. The stray flux in the secondary winding sectionscan alsol be increased by the use of magnetic material inserts at points other than those shown, but the arrangement of interrupted rings of magnetic material between the winding sections is the simplest and the safest arrangement in operation.

Although but one embodiment of the present` invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications maybe made -therein without departing from the spirit of the invention or from the scope of the appended claims.

. The invention claimed is 1. In an velectric transformer, a core, a primary winding upon said core, a second# ary winding divided into a plurality of sections arranged in spaced relation over said primary winding, and means arranged adthe secondary jacent said secondarfy winding to increase the voltag drop thereo an electric transformer, a core, a pri- 4. In an electric transformer, a core, a primary winding wound upon said core, a secondary winding divided into a plurality of sections connected into groups, the groups being arranged in interleaved spaced relation and being uniformly distributed over said primary winding, andinserts of conductive material arranged between each pair of said y secondary winding sections and in spaced relation therefrom to increase the voltage drop thereof.

5. In an electric transformer, a core, a. primary winding Wound upon said core, a secondary winding divided into a plurality of sections connected into groups, the groups being arranged in interleaved spaced relation and being uniformly distributed over said primary winding, and inserts of conductive material arranged between each pair of said secondary winding sections and in spaced relation therefrom to increase the voltage drop thereof, said inserts being laminated.

6. Inan electric transformer, a core, a primary winding wound upon said core, a secondary winding divided into a plurality of sections connected into groups, the groups being arranged in interleaved Yspaced relation and being uniformly distributed over said primary winding, and inserts arranged between each pair of said secondary winding sections and in spaced relation therefrom to A increase the voltage drop thereof, said inserts comprising laminations of conductive material and sheets of insulation arranged between the laminations.

7. In anelectric transformer, a core, a primary winding wound u on said core, a secondary winding divide into a plurality of sections connected into groups, the groups beinarranged in interleaved spaced relation and eing uniformly distributed over said primary winding, and inserts arranged between each pair of said secondary winding sections and lin spaced relation therefrom to. Aincrease the. voltage drop thereof, said inserts being'in the form of interrupted rings formed from laminations of conductive material and sheets of insulation arranged between the laminations.

to increase the voltage drop of said sections.

,December 6, 1932.

y M. l. lioore.

Acting Commissioner of Patents.

m 9. In an electric transformer comprising a winding divided into a plurality of sections arranged in spaced relation, and means ar.. ranged adjacent the respective sections of l, sai winding for increasing the voltage drop thereof.

In testimony whereof we have hereunto subscribed our names this 18th day of September A. D. 1931. ou STEFAN WIDMER. MAX HURLJMANN.

CERTIFICATE vOF CORRECTION.

raten No. l1,890,045. x

l STEFAN winmix, Er AL.

It is hereby certified that error vappears in the printed specification of the above numbered patent requiring correction as follows: H to printed specification, date of filing application in Germany, for September 17, 1931" read "September 17, 1930"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case In the Patent Office.

Signed and sealed this 23rd day of May, A. D. 1933.

(Seal) Page l, in the heading 

